<!DOCTYPE html><html><head>
  <title>Impossible rules (:root:first-child, etc)</title>
  <style type="text/css">
:root:first-child { background-color: red; }
:root:last-child { background-color: red; }
:root:only-child { background-color: red; }
:root:nth-child(1) { background-color: red; }
:root:nth-child(n) { background-color: red; }
:root:nth-last-child(1) { background-color: red; }
:root:nth-last-child(n) { background-color: red; }
:root:first-of-type { background-color: red; }
:root:last-of-type { background-color: red; }
:root:only-of-type { background-color: red; }
:root:nth-of-type(1) { background-color: red; }
:root:nth-of-type(n) { background-color: red; }
:root:nth-last-of-type(1) { background-color: red; }
:root:nth-last-of-type(n) { background-color: red; }
p { color: green; }</style>
  <link rel="author" title="Ian Hickson" href="mailto:ian@hixie.ch">
  <link rel="help" href="https://www.w3.org/TR/css3-selectors/#selectors"> <!-- bogus link to make sure it gets found -->
  <meta name="flags" content="">
 </head>
 <body>
<p>This line should be green (there should be no red on this page).</p>

</body></html>